Equal Channel Angular Pressing is a relatively novel method for deforming material to very high plastic strains, and not changing the billet shape. This research will use the DEFORM 3D to simulate the ECAP (equal channel angular pressing) die fatigue life design and assessment. Specifically this project will use the integrated FEM (finite element method) and CAE (computer aid engineering) methodology for the metal-forming die design. There are many factors such as the die angle, friction conditions, and the application of a back pressure affecting the microstructure and strain in-homogeneity. Then investigate the above method to design the best ECAP die. And then simulate the process that applying the die designed to extrude the aluminum 6061. The severe plastic defonnation (SPD) technologies can only get ultrafine strain, but according the Hall-Petch Strengthening Limit the best property can be got when the strain are about 10nm. The SMAT is the efficiency method to get the nano scale strain [K. Lu). Then the SMAT (surface mechanical attrition treatment) melhod is used to treat the ECAP specimens. Finally comparing the mechanical properties of specimens none treatment, ECAP treated, and the ECAP and SMAT treated individually. According to the data we expect to get the relationship between the grain size and the mechanical properties. And apply the new die design method to find the best ECAP die parameter.